Chair reclining mechanism

ABSTRACT

A reclining chair mechanism having its back supported for reclining rotation and forward shifting movement relative to a base, and its seat supported by overslung links which elevate the seat front rapidly upon forward shifting movement of the seat by the reclining rotation of the back, and wherein the seat is connected to the back in a manner such as to maintain the leverage of the occupant&#39;&#39;s weight upon the seat to counteract the leverage of the occupant&#39;&#39;s weight upon the back to prevent acceleration in the reclining movement and to maintain the chair in balance in various degrees of recline.

States Patent 1 James et a1.

[ Mar. 4, 1975 CHAIR RECLINING MECHANISM [75] I Inventors: Henry James;Carl B. Johnson, both of Pontiac, 111.

[73] Assignee: Pontiac Furniture Industries, Inc.,

Pontiac, Ill.

[22] Filed: June 28, 1973 [21] Appl. No.: 374,355

[52] US. Cl. 297/316, 297/340 [51] Int. Cl. A470 1/02 [58] Field ofSearch 297/316, 321, 322, 340, 297/341, 342

[56] References Cited UNITED STATES PATENTS 799,128 9/1905 Wilmot et a1.t. 297/316 X 2,240,850 5/1941 Knabusch et a1. 2,746,520 5/1956 Ducrot297/322 2,764,224 9/1956 Maurer 297/316 UX FOREIGN PATENTS ORAPPLICATIONS 1,255,403 0/1961 France 297/342 Primary Examiner-Roy D.Frazier Assistant Examiner-William E. Lyddane Attorney, Agent, or F irm-F itch, Even, Tabin & Luedeka [57] ABSTRACT A reclining chair mechanismhaving its back sup- .ported for reclining rotation and forward shiftingmovement relative to a base, and its seat supported by overslung linkswhich elevate the seat front rapidly upon forward shifting movement ofthe seat by the reclining rotation of the hack, and wherein the seat isconnected to the back in a manner such as to maintain the leverage ofthe occupants weight upon the seat to counteract the leverage of theoccupants weight upon the back to prevent acceleration in the recliningmovement and to maintain the chair in balance in various degrees ofrecline.

4 Claims, 5 Drawing Figures j CHAIRRECILINING MECHANISM Our inventionrelates to reclining chairs, and more specifically to linkage mechanismfor correlating the movement of the chair back and chair seat withrespect to each other and to the common base upon which they aresupported.

Reclining chair, as such, are an old and welldeveloped art that teachesmany arrangements for correlating the relative movement of seat and backto each other, as well as to other movable members and to the chairbases upon which they are supported. The present invention is concerned,however, with a linkage of the general kind described which has distinctadvantages over those earlier proposed for similar purpose in that itaccomplishes previously desired objectives without the disadvantagesthat heretofore have been associ ated with the attainment of theseobjectives.

In particular, the prompt elevation of the forward edge of the seat asan incident to initial reclining movement of the back has beenrecognized as a desired ob jective, and has been earlier attained by theoverslung linkage which is a component part of this invention. However,the mechanisms heretofore developed which have incorporated overslungseat supporting linkages have usually also been characterized by a rapidshift of influence of the occupants body weight from the portion of hisweight pressing down on the seat to that portion pressing rearward anddownward against the back, with the undesirable development of rearwardacceleration, i.e., an uncomfortable and even alarming falling-away"sensation.

Approaching from another tack, the prior art also discloses underslungseat mechanisms, which likewise elevate the seat as an incident toreclining movement of the back, and in such mechanisms, indeed, theinitial forward and only then upward movement of the seat increases theeffect of the occupants weight upon the seat, and more than counteractsthe effect of that portion of his weight bearing rearwardly anddownwardly upon the back. With underslung support of the seat section,however, the elevation of the seat incident to the reclining of the backis much delayed as compared with that of the overslung linkage, and fullrecline of the back can require more effort to maintain than isconducive to repose.

Wherefore, a principal object of our invention is to utilize fully theadvantage of the overslun g seat-support linkage, viz., the rapid riseof the seat, particularly at the front edge, upon initial recline of theback, but to simultaneously obviate the difficulties experienced inearlier suchattempts, viz., the rapid transfer of influence to theportion of the occupants body weight exerted against the chair back.

In short, we propose by our invention to have the advantage of thefast-rising seat-elevating movement afforded by an overslungseat-support linkage, while at the same time maintaining a balancebetween the respect influences of body weight upon the seat and upon theback to maintain the chair in reasonable balance at any position ofrecline without requiring the auxiliary or artificial motion-retarderswhich usually increase the muscular effort required to change theattitude of the reclining chair.

It is our further object to provide a reclining chair which attains theabove objective by a movement of the seat and lower portion of thebackrest forwardly on the 2 chair base, which has the further desirableresult of maintaining the center of gravity of the chairv and itsoccupant more or less fixed throughout the reclining movement, as wellas minimizing the wall or other clearance required behind the chair topermit the same to be reclined. I

Our still further object is to provide a linkage of the kind describedin which the respective linkage members are under load in all positionsso that inevitable wear and consequent loosening of the riveted pivotalconnections of the linkage are not made evident by rattling, as sometimeoccurs when recline linkages are used on rocking bases in so-calledrocker-recliner chairs.

Our invention, and its attainment of the foregoing objectives, will beevident from the following specification, taken in, conjunction with theaccompanying drawings in which FIG. 1 is a perspective view of ourrecline linkage as seen from a rear quarter with portions of the seatbracket broken away to better illustrate the remaining parts;

FIG. 1A is a perspective view of only the seat bracket of the linkage,shown in full immediately above its posi- .tion in FIG. 1 so that itsform will be clear;

FIG. 1B is an enlarged perspective view of one element of the linkageshown in the same attitude it assumes in FIG. 1 but removed from contextfor clearer illustration;

FIG. 2 is a diagrammatic side elevation of the linkage in sittingposition, showing its position in the chair sug gested by the brokenoutline; and

FIG. 3 is a similar diagrammatic side elevation of the linkage (andchair) in recline.

FIG. 1 illustrates a linkage in accordance with the invention, one oftwo such linkages, each a mirror image of the other, required for eachchair. The linkage is attached to the base frame 10 ofa chairillustrated in broken outline in the drawings, by means ofa base bracket12, and the chair back 14 is mounted on the base by means of aback-support bracket 16 whose path of movement relative to the basebracket is determined by a pair of links 18 and 20. The length andangularity of the back support links 18 and 20 are such that therotation of the chair back 14 by the reclining movement moves the lowerend of the back forwardly of the base through a fixed path incident tosuch rotation.

The seat 22 of the chair is carried on a seat bracket 24 which isconnected for movement conjointly with the back. The seat is supportedtoward itsfront end by a link 26 pivoted to the seat bracket 24 and tothe base bracket 12 and is supportd adjacent its rear end by its pivotalconnection to a bell crank lever 28 which is itself pivotally mountedupon the forward back support link 20, and controlled in its angularityrelative thereto by a control link 30 pivoted respectively to the bellcrank lever 28 and to the back support bracket 16. The controlled actionof the bell crank lever 28 incident to reclining movement of the back isto thrust the seat forwardly, as indicated by the transition from FIG. 2to FIG. 3. Coincident therewith, the upper end of the seat support link26 swings upwardly as well as forwardly, and pitches the front end ofthe seat upwardly.

The forward motion of the seat bracket 24 caused by its pivotalattachment to the bell crank lever 28 is the result of a dual movement,viz., the forward rotation of the forward back-support link 20, and theconcurrent movement of the bell-crank lever 28 on the linkcounterclockwise (as seen in the drawings) caused in turn by thecounterclockwise rotaion of the backsupporotbracket 16 relative to theforward backsupport link 20 and transmitted to the bell crank 28 throughthe control link 30. As this movement proceeds, the leverage of theoccupants weight upon the seat 22, exerted upon the backrest bracket 16through the bell crank lever 28 and the control link 30, is multiplied,and counteracts the influence of the rearward pressure of the greaterbody weight of the upper portion of the body upon the chair back 14during the recline movement.

When it becomes understood that the function of the bell crank lever 28is to increase the moment of the seat weight in order to counterbalancethe increasing moment of the back weight as the back reclines, and thatthis countermoment is applied in the preferred embodiment illustrated byforces applied both to the backsupport bracket 16 (through the controllink and to the forward back-support link 20 (through the bell crank28), it becomes evident that the countermoment might also be applied bythe suitable application of force to either of the back-support links 20and 18 alone, or indeed to the back rest itself.

For example, we have contemplated the inversion and re-shaping of thebell crank 28, and its connection by means of a control link, such asthe link 30, to the base bracket 12 instead of to the back-supportbracket 16. In such case, the control link would be in tension insteadof in compression, and the counterbalancing effect of the seat weightwould be applied as a force opposing the forward rotation of the forwardbacksupport link 20. However, we prefer the illustrated embodimentbecause as may be appreciated from FIG. 3, the toggle formedby the backsupport bracket l6 and the rearward back-support link 18 approachesalignment in the full recline position. In these circumstances, theattachment of the control link 30 to the. back-support bracket 16, asillustrated, applies a counter-force directly to the back-supportbracket 16 to break the toggle knee, and assist the return of the backrest to the upright position.

We conceive it also possible to connect the control link 30 to therearmost back-support link 18, again with some re-shaping of the lever28 to achieve the desired result.

On the other hand, the application of a countermoment directly to theback rest alone, as by pivoting the rearward portion of the seatdirectly upon an'extension of the back-support bracket 16, whileeffective in counterbalancing the back in the setting of an overslungseat-support linkage, is undesirable for other overriding reasons, viz.,because the rearward movement of the lower end of the back away from theseat incident to recline is undesirable for its shirttail pulling effectand also for its failure to provide the lower lumbar support thatresults from the illustrated linkage, in which the lower supportingsurface of the back rest moves but little forwardly or rearwardly of theseat during the reclining movement.

Referring in greater detail to the drawings and particularly FIG. 1, itwill be seen that the base bracket 12 is essentially a length of angleiron with its vertical flange directed upwardly on the inner side of thebracket, and having at its rear end an upwardly inclined outriggerextension 32. The horizontal flange of the base bracket 12 is providedwith a number of anchoring holes 34 for securing the same to a woodenbase by means of any suitable fasteners, preferably screws. In each ofthe drawings, the linkage is depicted as mounted upon a fixed chair base10, suggesting its application to an ordinary reclining chair, but itshould be understood that the linkage is equally applicable to socalledrocker-recliners in which case the base mounting bracket 12 is securedin the same fashion to the rocker element instead of to a fixed base asthe drawings indicate.

The aforementioned outrigger 32 of the base bracket 12 provides anappropriately positioned point of attachment for the lower end of therear back-support link 18, the upper end of which is suitably pivoted tothe lower end of the back-support bracket 16. The forward back-supportlink 20 is boomerang shaped and pivoted at the juncture of its two armsto the upstanding flange of the base bracket 12, and at the upper end ofits rearwardly and upwardly extending arm to the lower forward end ofthe back-support bracket 16. It will be apparent that the two links 18and 20, constituting together with the base bracket 12 and thebacksupport bracket 16 a four-bar trapezoidal linkage, fully determinethe path of movement of the back-support bracket 16, which as shown bycomparison of FIGS. 2 and 3, moves forwardly relative to the basebracket 12 as it is rotated counterclockwise by the reclining movement.

As shown especially in FIG. 1, the vertical flange of the base bracket12 and the side plate of the back support bracket 16 are in the sameplane, the back support links 18 and 20 being mounted on the insidesurfaces of those brackets. The other, shorter arm 36 of theboomerang-shaped back-support link 20 engages a stop plate 37 secured tothe underside of the base bracket 12, and thus determines the upright orsitting position of the linkage.

The back-support bracket 16 has an inwardly extending flange 38 toprovide a mounting seat for the frame of the backrest 14, holes 40 beingprovided therein to secure the back to its supporting bracket by meansof screws. The lower end of the flange 38, by its contact with the rearback support link 18, provides a stop to determine the fully reclinedposition (FIG. 3).

The seat support bracket 24 is a downwardly-open channel in its forwardportion, thus providing opposed flanges for mounting the operatinglinkage of a footrest 42. Such linkage, being irrelevant to the subjectmatter shown and claimed, is omitted, and may be any suitable footrestsupport mechanism operated either by the reclining action of the seatand back, or by separate lever action, as may be desired in a particularapplication.

The rearward, angle portion of the seat bracket 24 (FIG. 1A) includes adepending vertical inner flange 44 of gradually increasing depth fromfront to rear, providing forwardly of its mid point a convenient sitefor the pivotal attachment of the forward support link 26. For reasonsnot relevant here, the flange 44 has a circular boss stamped outwardlytherefrom so that the pivot rivet at the upper end of the link 26 may beflush with the forward surface of the flange. The more rearward deepestportion of the flange 44 is the point of the pivotal attachment of theseat bracket to the lower forward pivot of the bell crank lever 28,while rearwardly of its pivotal attachment to the bell crank, thevertical flange 44-of the seat support bracket recedes upwardly to adepth commensurate with its horizontal flange.

The forward portion of the seat bracket 24, as earlier noted, is aninverted channel whose outer flange 46 is pierced coaxially with therivet hole for the upper pivot of the link 26, to provide a work hole 48large enough for access by the riveting tool.

Because the seat bracket 24 is mounted outwardly of the back-supportlinks 18 and 20, and outwardly of the bell crank 28 and the control link30, its rearward portion is shown in broken outline in several of thedrawings in order not to obscure those elements of the linkage.

In order to provide the necessary moving clearances for the action ofthe several members of the linkage in the transition from FIG. 2 to FIG.3, relief in depth is provided by offsets in the bell crank lever 28, inthe control link 30 as well. Specifically as noted particularly in FIG.1B, the body of the bell crank lever 28, a triangular stamping, occupiesthree planes. At the site of its pivotal attachment to the seat bracket24, it is embossed outwardly as at 50, and at the site of its pivotalattachment to the forward back. support link 20, it is embossed inwardlyas at 52, leaving its third pivot site 54 in the mid-plane. Clearancefor the movement of the control link 30 is thus provided between thevertical flange 44 of the seat bracket and the forward back support link20. The control link 30 itself is offset at its upper end to provideclearance for its passage over the head of the upper pivot rivet of theback-support link 20.

Because of the balance achieved in this linkage, it is possible toconstruct the upholstered seat and arms for attachment as an integralunit to the seat bracket 24. This is particularly desirable in therockerrecliner chairs for it not only eliminates the wear and noiseresulting from movement of the seat within and relative to the armframes, it also lends greater flexibility of styling as contrasted tochairs of current manufacture having a two-phase reclining movement,i.e., a first rearward shifting of the seat to extend the leg rest to anintermediate so-called TV position, essentially without substantialreclining movement of the back. Such chairs, by requiring fixed armrests against which the occupant can push himself and the seatrearwardly, are limitd in their styling capabilities inasmuch as theycannot satisfactorily use a T-shaped seat cushion.

As earlier indicated, the sitting position of the chair is determined bythe engagement of the lower arm 36 of the forward, boomerang backsupport link with the stop plate 37 secured to the horizontal flange ofthe base bracket 12. This is shown both in FIG. 1 and FIG. 2.Particularly from FIG. 2 it will be noticed that the support link 26 forthe seat is inclined upwardly and rearwardly in sitting position so thatthe occupants weight upon the seat maintains a compressive loading notonly upon the support link 26 of the seat, but also upon the controllink 30. It will further be apparent that each one of the pivots of thelinkage likewise remains under load in every conceivable position thelinkage may occupy. This constant loading has the advantage, as earlierindicated, of eliminating clicking noise in the linkage when the same isused in a rocker-recliner, i.e.,

6 when the linkage in the position shown in FIG. 2 is rocked back andforth without relative movement of the seat and back of the chair.

Further with regard to FIGS. 2 and 3, it is apparent that as the back 14is reclined, its lower end, being immediately adjacent to the backsupport bracket 16, moves forwardly, as does the seat. The center ofgravity of the occupant, different of course in persons of differentstature, is usually located in the lower abdomen. The position of thatcenter, as may be appreciated by comparison of FIGS. 2 and 3, willremain relatively unchanged between the sitting and the fully reclinedpositions, and in intermediate positions as well. This tends to providegood inherent balance without the need either of counterbalancingsprings, or of motionretarders or snubbers, suchas are often requiredeither to compensate for over-shifting of body weight or to provideartificial retardation for movement that would otherwise be dulyaccelerated or abrupt.

The features of our invention believed new and patentable are set forthin the appended claims.

What is claimed is: 1. In a reclining chair having a base, a seat, aback, and linkage means at each side of the chair interconnecting saidback and seat and mounting the same upon said base for movement relativethereto and to each other from a sitting position to a recliningposition,

the improvement wherein said linkage means supports the back upon thebase for forward shifting movement through a fixed path relative to thebase as an incident to recline of the back and includes at least oneback link extending upwardly from the base to back and pivoted to bothfor rotation forwardly on the base by the recline of the back, a seatlink connecting the forward portion of the seat to the base and beinginclined rearwardly and'upwardly from the base to the seat when in saidsitting position, and a lever pivoted on said back link and connected bya control link to a portion of said chair other than said seat and withrespect to which said back link is relatively movable upon the reclineof the back, said lever being also pivoted to the rearward portion ofthe seat to support the seat and to move the seat forwardly relative tothe base of the recline of the back.

2. The improvement of claim 1 wherein said back is supported by twolinks each pivoted to the base and extending upwardly therefrom topivotal connections to the back to form a trapezoidal four-bar linkagewith said base and back and wherein said lever is pivoted to theforwardmost one of said two links, and said control link connects saidlever to one of said base, said back, or the other of said two links.

3. The improvement claimed in claim 1 wherein said control link rotatessaid lever to advance the pivotal attachment of the lever to the seatfaster than the pivot of the lever to said back link.

4. The improvement claimed in claim 2 wherein said lever is a bell crankwhose pivot to said forward-most link is disposed between and above thepivotal connections of the bell'crank to said seat and to said controllink, and said control link is pivoted to said back.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTIONPATENT NO. 3,869,172

DATED March 4, 1975 INVENTOMS): Carl B. Johnson and Henry James Column6, line 45 (last line of Claim 1) "of" (first occurrence) should read bySigned and Scaled this second Day Of September1975 [SEAL] A ttes t:

RUTH C. MASON C. MARSHALL DANN Arresting Officer ('nmmissimzcr uj'lalcmsand Trmlvmarks

1. In a reclining chair having a base, a seat, a back, and linkage meansat each side of the chair interconnecting said back and seat andmounting the same upon said base for movement relative thereto and toeach other from a sitting position to a reclining position, theimprovement wherein said linkage means supports the back upon the basefor forward shifting movement through a fixed path relative to the baseas an incident to recline of the back and includes at least one backlink extending upwardly from the base to back and pivoted to both forrotation forwardly on the base by the recline of the back, a seat linkconnectiNg the forward portion of the seat to the base and beinginclined rearwardly and upwardly from the base to the seat when in saidsitting position, and a lever pivoted on said back link and connected bya control link to a portion of said chair other than said seat and withrespect to which said back link is relatively movable upon the reclineof the back, said lever being also pivoted to the rearward portion ofthe seat to support the seat and to move the seat forwardly relative tothe base of the recline of the back.
 2. The improvement of claim 1wherein said back is supported by two links each pivoted to the base andextending upwardly therefrom to pivotal connections to the back to forma trapezoidal four-bar linkage with said base and back and wherein saidlever is pivoted to the forwardmost one of said two links, and saidcontrol link connects said lever to one of said base, said back, or theother of said two links.
 3. The improvement claimed in claim 1 whereinsaid control link rotates said lever to advance the pivotal attachmentof the lever to the seat faster than the pivot of the lever to said backlink.
 4. The improvement claimed in claim 2 wherein said lever is a bellcrank whose pivot to said forward-most link is disposed between andabove the pivotal connections of the bell crank to said seat and to saidcontrol link, and said control link is pivoted to said back.